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#1074524 07/21/22 07:45 PM
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Question / how many banks are there per each side on the 305? I have a Y pipe so it’s not true dual exhaust. Also, it’s running rough, and have had enough experience that when a o2 sensor is shot, it tend to sputter in idle and during acceleration. I’m not sure exactly but the check engine doesn’t come on, but again not sure if these year cars will cause the CEL to pop on?

83Monte305 #1074531 07/22/22 12:49 AM
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Also can you splice the wires and not use the connectors? The plastic melted from laying on the manifold and pretty much gone

83Monte305 #1074532 07/22/22 01:11 AM
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There is one O2 sensor on these cars, it's in the drivers side exhaust manifold. It can be a xxxx to get out. Personally, I would try to find the correct wiring pigtail and repair the harness side of the sensor wires. Good luck!!


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86ttop #1074533 07/22/22 02:26 AM
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Rock Auto is a good source for OEM wiring pigtails. I suggest not hard wiring the O2 sensor wiring to the harness wires. If you ever needed to disconnect the O2 sensor, you'll have to cut the wires.


87 SS, Harwood hood, UMI trailing arms. Hooker 2050 Headers (Jet Hot Coated). Hooker Cat-Back Exhaust, Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow roller rockers, TCI 2400 stall converter, Denny's 3.5" Driveshaft, GBodyParts GNX Replica Wheels 18x8 & 18x9. F-Body Serpentine Belt Sys.
83Monte305 #1074535 07/22/22 04:50 AM
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Might be a good time to wire in a 3 wire connector for a heated O2 sensor upgrade.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
83Monte305 #1074536 07/22/22 02:59 PM
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FYI, If you do plan on connecting bare wires and/or slicing harnesses, I've found the leads on new O2 sensors are very difficult to solder, and I'm not sure I'd trust crimps. The harness side should be easier, so I'd go along with other suggestions and get the replacement plug from Rock Auto or somewhere similar and fix it right, then tie up out of the way somewhere so it doesn't happen again.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
83Monte305 #1074542 07/22/22 09:32 PM
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Good stuff guys - how does the upgraded 3-wire heated sensor work/benefit, and what’s all involved ?

83Monte305 #1074548 07/23/22 12:28 AM
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The o2 sensor needs to heated up by the exhaust gases to function properly. If it gets too cool then the ECM may not get any feedback from the o2 sensor and go into open loop. TBH I've never had this issue using oe cast iron manifolds or shorty headers for that matter. You'll get the most benefit if you're using long tube headers and experience this switching between open/close loop usually while sitting idle.


1985 GMC Caballero 4.3L V6 TBI 200C w/ 2.41 posi
86 Monte Carlo SS BBC396 M20 w/ 3.42 posi screen name whip rust i.p.
83Monte305 #1074550 07/23/22 02:57 AM
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My 305 is running rough and rich. Since the car is computerized carb, does it work in sync with the o2 sensor? Also Is there a way to check that the o2 send lead wire is functioning properly by checking volts? I pulled the sensor off today and waiting for a new one to arrive. I actually started it and ran it without and the check engine light didn’t come on, not sure if that’s not working, burned out bulb or what… so would like to check that wire

83Monte305 #1074552 07/23/22 03:41 AM
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Yes, the stock Monte Carlo SS computer works with the stock O2 sensor. It has been awhile since I have worked on this circuit, but if you place a volt meter on the output from the O2 sensor you should see a varying output when it is up to temp. I did this by back-probing the connector. The signal will vary from rich to lean (I forget the mv reading), you will see it switch from high to low voltage continuously. That means it is working correctly. The stock O2 sensor in the G-body is a narrow band. It switches from rich to lean continuously and the computer takes an average to determine fueling. Maybe other members can chime in on this.


87 SS, Harwood hood, UMI trailing arms. Hooker 2050 Headers (Jet Hot Coated). Hooker Cat-Back Exhaust, Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow roller rockers, TCI 2400 stall converter, Denny's 3.5" Driveshaft, GBodyParts GNX Replica Wheels 18x8 & 18x9. F-Body Serpentine Belt Sys.
83Monte305 #1074553 07/23/22 04:17 AM
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Originally Posted by 83Monte305
Good stuff guys - how does the upgraded 3-wire heated sensor work/benefit, and what’s all involved ?


The stock one wire O2 sensors lack built in electric heaters. This causes one wire sensors to cool off during prolonged idle and return to open loop mode, aka cold engine mode. I had this happen while tuning the engine, through I do have headers. The GM repair manuals state this can happen in stock cars. Heated O2 sensors don't cool off during idle and stay in closed loop. They also are more accurate by being less lazy and also last longer than one wire sensors. Cool and old O2 sensors can be very slow switching which is what lazy refers to. You can purchase the connector kit on Ebay for pretty cheap. Also need to watch out for upstream exhaust leaks that can throw off O2 readings.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
83Monte305 #1074556 07/23/22 02:52 PM
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If your wanting to get your car running correctly and keep it running correctly like factory there are some suggestions that have already been made and I will add a few more . I know it sucks spending money on things that are not go fast goodies but these are all things I feel are essential if your wanting to work on your own car, without some of this stuff you are just shooting in the dark and it will be hard for others to help with out the needed info . Once again this is all just my opinion. The bare minimum I would have is the shop manuals, dwell meter, timing light, vacuum gauge, fuel pressure gauge and a multimeter. I know this doesn't deal with your o2 sensor question directly but I wasn't sure which post of yours to put this on.

Watch these videos to understand how the computer controlled carburetor and its systems works. These are videos that gm techs were trained with at the time. This is free firsthand knowledge about your exact car.
Video 1 https://youtu.be/8jGqIBAUnMY
Video 2 https://youtu.be/vDStPuQyo_Q
Video 3 https://youtu.be/OVrvSDuFOjM
Video 4 https://youtu.be/wbscqaLYNjw

These manuals are grade A+ In my opinion and would be exactly what the mechanic would use at the chevrolet dealership in 1983 to deal with all aspects of your car. I recommend getting the electrical supplement also. Doug Roes book is decent and I recommend it but I think this manual is better overall and deals with complete car..

Manual

https://www.ebay.com/itm/2749729065...r=&widget_ver=artemis&media=COPY

Electrical supplement

https://www.ebay.com/itm/3850190824...r=&widget_ver=artemis&media=COPY

Dwell meter

https://www.ebay.com/itm/2849017492...r=&widget_ver=artemis&media=COPY

Timing light, I've had good luck with this one.

Innova 3568 Digital Timing Light https://a.co/d/99UkoYP

Vacuum gauge for various troubleshooting.

OTC 5613 Vacuum/Pressure Gauge Kit https://a.co/d/6fcLgnU

Fuel pressure gauge, with the various pieces, hose calmps and fuel hose I was able to use this on stock fuel line and quadrajet.. you have to break the line at carb loose but it works.

Gauge
MEANLIN MEASURE 0~15Psi Stainless... https://www.amazon.com/dp/B08HRW7ZNS?ref=ppx_pop_mob_ap_share

T block 3/8" for gauge and barbs
Eaton Weatherhead 3700X6 Brass CA360 Fitting, Tee, 3/8"NPT Female https://a.co/d/4pXy1Em

Barbs you will need 2
EDGE INDUSTRIAL 3/8" Hose ID to 3/8" 45° Male Flare Straight Brass Fitting Fuel / AIR / Water / Oil / Gas / WOG (Qty 01) https://a.co/d/9zQMrn9

Threads into carb.
Midland 38-874 Brass Inverted Flare Male Swivel, 90 Degree Elbow, 3/8" Hose ID x 3/8" Tube OD https://a.co/d/4itjw7Y

Threads onto hard fuel line
EDGE INDUSTRIAL 3/8" Hose ID to 3/8" 45° Female SAE Flare Brass Swivel Connector Fuel / AIR / Water / Oil / Gas / WOG (Qty 01) https://a.co/d/3cnIBYO

Fuel line
LDR Industries 516F385 5' Bag Fuel Line, 3/8" https://a.co/d/1pH2Qtl

To make this:
[Linked Image]



You need a good multimeter for troubleshooting various circuits and sensors, something like this. What I listed is just an example, I like fluke but it's way overkill for most.

Klein Tools MM600 Multimeter, Digital Auto-Ranging, AC/DC Voltage and Current, Temperature, Frequency, Continuity, More, 1000V https://a.co/d/5mXw9Pk

If you are really wanting to dig in to ccc quadrajets the Doug Roe book is good but I think most would be fine with above manual but it's a good read with good info.

https://www.ebay.com/itm/2248566782...r=&widget_ver=artemis&media=COPY

For ccc rebuild parts the best place is Cliff Ruggles, he also wrote a quadrajet book but it just focuses on non ccc quadrajet. He has lots of knowledge and good parts if needed.

https://cliffshighperformance.com/

https://cliffshighperformance.com/product/quadrajet-ccc-rebuild-kit

Thexton makes tools to help with tuning and rebuilding the ccc, they are hard to find but can usually be found on ebay from time to time. Thexton tool kit 362, 370, and 380.The tools are not necessary but they help, if you search here and at 3rd gen.org there are work arounds if you don't have tools

https://offerup.com/item/detail/28876930

An obd1 scanner can also be useful but not needed unless really digging In. If you have a cel you can jumper and get codes that way and look them up in the above e manual. Obd1 scanners will let you get readings of sensors also.

I get lots of useful info by searching this forum. As an example I usually go to Google and type "montecarloss 3 wire o2 forum" or "montecarloss Vacuum diagram forum". I will also ask here after I've searched just to get opinions on the subject I'm working on. I'm not trying to be a smartass it's just how I do it. Also lots of good info at https://www.thirdgen.org/. If you go to
http://montecarloss.com click on information box then click technical information there is tons of resources.

For hard to get parts I usually go to rock auto, or ebay and hope to find them. Original Parts Group (opgi ) has some sensors but they won't be cheap. Mike's Montes has lots of parts and if it's not on his site it's worth a call.

Good Luck











Last edited by 88ssBrent; 07/23/22 03:10 PM.
83Monte305 #1074557 07/23/22 03:39 PM
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Thanks guys For the info, good stuff each post. Brent excellent man - I’m going to take some time later and write all this out and watch the vids. Anyone live in or near Pittsburgh?

83Monte305 #1074558 07/23/22 03:44 PM
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Heated o2 is a nice upgrade, when i still had the ccc system I used one but also had longtube headers. I think you should test your o2 before throwing money at spare parts, it can get expensive doing it that way but that decision is up too you. For the 3 wire upgrade this is what I used.

Ntk 21003 o2 sensor $17

https://www.ebay.com/itm/3339049540...r=&widget_ver=artemis&media=COPY

1 wire to 3 wire adapter $16

https://www.ebay.com/itm/1632981263...r=&widget_ver=artemis&media=COPY

Add a circuit fuse tap

https://www.autozone.com/electrical...sories/p/bussmann-atc-fuse-tap/32414_0_0

If you use the above adapter the white wire plugs into your existing 1 wire harness, black wire goes to ground, and red wire goes to a switched hot wire. Most people put the add a circuit fuse tap into the c/h fuse at the fuse block under dash on driverside and use that as there switched hot. Your choke heater circuit has power to spare. I originally did it this way but have since redid a lot of my car wiring. 5 amp fuse is plenty for the heated o2.


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